Leiomyosarcoma of the Maxilla: A Case Report and Literature Review

Leiomyosarcoma is a malignant tumor arising from smooth muscle cells accounting for 10-20% of soft tissue sarcomas and less than 2% are located in head and neck region. We report a case of leiomyosarcoma of maxilla in a 26-year-old female patient referred to Shahid-Beheshti University of Medical Sciences, Faculty of Dentistry. Patient complained of swelling of left side of the face from 5 months ago without a history of significant illness. Clinical examination showed asymmetric swelling of left side of the face with tenderness. The lesion in the left buccal vestibule was tender to the touch and contained erythematous mucosa with a firm tissue. Results of the neck computed tomography (CT) scan indicated mucosal thickening in the left maxillary sinus. In the preoperative magnetic resonance imaging (MRI), a mass with an estimated size of 4.7×3.1×3.0cm was found, extending from the posterior wall to the posterolateral wall of the left maxillary sinus, causing impression and remodeling of the sinus wall. Incisional biopsy was preformed and immunohistochemistry suggested leiomyosarcoma. Partial maxillectomy of the posterior maxillary walls was performed, using an intraoral incision and dissection from the maxillary vestibule up to the mandibular vestibule. The tumor was excised using frozen section. Pathological examination reported the lesion compatible with leiomyosarcoma, with all surgical margins free of tumor. Post-operative MRI showed no definite mass in the region. In conclusion, according to the present results, the clinical features of leiomyosarcoma of the maxilla are clear, and diagnosis is feasible.

In oral and maxillofacial examination, asymmetry of the face with swelling on the left cheek was observable.
The skin of the face and neck was normal. The area of swelling was tender, without paresthesia and or pain.
The lesion in the left buccal vestibule was tender to the touch and contained erythematous mucosa with a firm tissue ( Figure 1). No other significant finding was observed in her complete exam.

Paraclinical exams
The complete blood cell count (CBC) and biochemical markers, including blood urea nitrogen (BUN), create nine, calcium, phosphorous, sodium, potassium, bilirubin (direct and total bilirubin), alanine aminotransferase  Maximum mouth opening was decreased to less than 4-5mm when it was decided to do the second operation.
Under fiber optic assisted nasal intubation and general

Discussion
According to a review of the literature (shown in Table   1), leiomyosarcoma is a rare and aggressive soft tissue tumor, originating from smooth muscle cells, which tends to occur in the alimentary tract, uterus, and retroperitoneum. Only 3% of leiomyosarcoma cases occur in the head and neck regions [6]. The most common sites in the sinonasal tract include the maxillary sinus, nasal cavity and ethmoid sinuses [7]. Leiomyosarcoma of the sinonasal tract may originate from the smooth muscles of blood vessels, which are the only structures containing smooth muscles in the area [8]. Our patient was diagnosed with leiomyosarcoma in the left maxillary sinus, which is a rare observation. Generally, the treatment of leiomyosarcoma poses a challenge due to the high rate of recurrence and metastasis and poor prognosis. Our patient was 24 years old, which is the most common age for leiomyosarcoma with the age range of 21-73 years [9]. Leiomyosarcoma of soft tissue commonly presents as a slow-growing painless mass, which can cause a variety of symptoms, depending on its location [9]. Previous studies have reported leiomyosarcoma as a large soft tissue mass [3,7,[10][11], which can invade the maxillary walls and cause obstruction and destruction [10][11][12]. The common presentations in the maxillofacial region include nasal obstruction, epistaxis, local pain, and facial swelling. Patients initially notice facial swelling with stretched skin [7,11,[13][14]; long-term rhinorrhea is also possible [15]. In cases where the tumor invades the orbit, eye movements may be restricted [11]. The oral mucosa may remain normal or become erythematous, similar to our case, who reported oral lesions in the left   [6,14]. To confirm the diagnosis of the lesion, an incisional biopsy was taken. The results of the biopsy showed spindle-shaped cells with oval to elongated nuclei, mitosis, hyalinization, necrosis, eosinophilic cytoplasm, and inflammatory infiltration [7,11,17]. In our case, the IHC analysis of the specimen showed vimentin, SMA and desmin staining [6,18], indicative of leiomyosarcoma.
The gross pathology of leiomyosarcoma indicated a firm reddish-brown appearance on the surface and a solid yellowish-white fibrous cut surface with hemorrhage and necrosis [5]; a grayish color was also observed [6].
Moreover, the pathological features were consistent with the biopsy results [5][6]. Studies of maxillofacial leiomyosarcoma show poor prognosis and a high recurrence rate [19][20]. Overall, surgical treatment with clear margins is recommended to control the recurrence of leiomyosarcoma [5]. The risk of recurrence is higher in maxillary leiomyosarcoma with a poorer prognosis, because of difficult access to some anatomical sites and free margins [5,12]. Overall, an accurate diagnosis and a proper combined treatment plan can produce favorable outcomes [5].
Surgery, chemotherapy, and radiotherapy are treatment modalities of leiomyosarcoma, based on clinical and tumor features. Surgical excision seems to have the best outcomes, if the tumor could be removed completely.
Leiomyosarcoma is generally considered radio resistant, but the benefits of radiotherapy have been also reported.
Chemotherapy is often used for metastatic lesions, as well as inoperable tumors as a palliative therapy [20]. In cases where local lymph nodes are engaged, surgery with wide resection of tumor margins is recommended, given the infiltrative nature of the tumor [7,11]. In this regard, Pasrad et al. [11] used total maxillectomy, followed by radiotherapy and showed no recurrence in an 18-month follow-up. Similarly, Wada et al. [12] reported a three-year recurrence-free survival.
However, in some cases with orbital involvement and metastasis, mortality has been reported, despite all available treatments [11]. In our case, due to the patient's emphasis on esthetics, an intraoral approach was used for tumor excision to avoid facial scarring, despite tumor invasion into the infratemporal region. Tumor excision with frozen section was carried out, the results of which were normal pathologically and were confirmed in the follow-up MRI at six months after the procedure. For treatment, eight courses of chemotherapy (Vincristine Richter 1mg/mL*2 and Endoxan ® ) and radiotherapy were administered. The recurrence of primary oral leiomyosarcoma is estimated at 34%, and distant metastasis has been reported to occur in 35% of patients. Lungs are the most common sites for oral leiomyosarcoma metastasis. A five-year survival rate has been reported for these patients, and metastasis involving the bone shows a poor prognosis [20]. The definitive diagnosis of leiomyosarcoma is based on histological examination, and surgical excision is the pre-ferred method of treatment. In conclusion, according to the present results, the clinical features of leiomyosarcoma of the maxilla are clear, and diagnosis is feasible.
The intraoral approach used in this case report could help avoid facial scars. However, further studies are needed to introduce a proper treatment plan for better prognosis and lower recurrence. Written and verbal informed consent for patient information and images to be published was provided by the patient.

Conclusion
According to the present results, the clinical features of leiomyosarcoma of the maxilla are clear, and diagnosis is feasible. The intraoral approach used in this case report could help avoid facial scars. However, further studies are needed to introduce a proper treatment plan for better prognosis and lower recurrence.